The present invention relates generally to connectors for terminating coaxial cable. More particularly, the present invention relates to axially compressible connectors for hard-line or semi-rigid coaxial cables.
Coaxial cables are commonly used in the cable television industry to carry cable TV signals to television sets in homes, businesses, and other locations. A hard-line coaxial cable may be used to carry the signals in distribution systems exterior to these locations and a flexible coaxial cable is then often used to carry the signals within the interior of these locations. Hard-line or semi-rigid coaxial cable is also used where a high degree of radio-frequency (RF) shielding is required.
The hard-line cable includes a solid wire core or inner conductor, typically of copper or copper-clad aluminum, surrounded by a solid tubular outer conductor. The outer conductor is also usually made of copper or aluminum. Dielectric material or insulation separates the inner and outer conductors. The outer conductor is covered with a cable jacket or sheath of plastic to provide protection against corrosion and weathering.
One type of connector for hard-line coaxial cables employs radial compression crimping to electrically and mechanically connect parts of the connector to the cable. Typically, a sleeve within the connector is compressed by a crimping tool. The sleeve may have slots, flutes, threads and the like to assist in the mechanical connection between the sleeve and the outer conductor of the cable. Such connectors are shown, for example, in U.S. Pat. Nos. 4,408,821, 4,469,390, 5,120,260 and 6,042,422.
Radial crimping, however, often does not apply compressive force evenly to the outer conductor or alternatively to the outer tubular jacket of the outer connector. Such uneven compression can form channels for infiltration of moisture into the coaxial cable connection and consequently lead to the degradation of the signal carried by the cable.
Threaded cable connectors, as shown in U.S. Pat. Nos. 5,352,134 and 6,019,636, have been employed to provide more even compression of the connector. Such connectors typically utilize some form of locking mechanism that radially compresses the outer conductor of the cable against a tubular insert shaft upon axial threaded movement of the connector components to retain the cable in the hard-line connector. The locking mechanism may include a conical sleeve surrounded by an outer sleeve which forces the conical sleeve to radially compress upon axial movement of the outer sleeve with respect to the conical sleeve. The length of the conical closure sleeve typically closes the full length of the mechanism with equal forces around the circumference of the insert shaft. The resulting forces closing down on the coaxial cable compress the cable around the outside of the insert shaft creating a formed bond on the outside surface.
One problem with conventional hard-line connectors is the difficulty involved in removing a cable from the connector upon disassembly of the connection. Depending on the type of cable, insulative material or dielectric is often left on the inside of the outer conductor of the cable after coring or cable preparation. This can lead to high forces required to remove the cable from the connector if the bond between the inner diameter of the outer conductor and the outer diameter of the insert shaft are not broken mechanically when the connector body and the back-nut are being removed from the coaxial cable.
Typical connector removal from the cable is by hand. If the connector can not be removed, installers tend to use devices, such as hammers and wrenches, to hit or bang the connector off the cable. If this fails, the installers will cut the connector off the cable and discard the connector.
Accordingly, it would be desirable to provide a hard-line coaxial cable connector that is easily removed from the coaxial cable after use.